Method and apparatus for separating magnetic ores.



J. WEATHERBY. METHOD AND APPARATUS FOR SEPARATING MAGNETIC ORES.APPLICATION FILED JUNE 12, 1915.

1,218,916. Patented Mar.13,1917.

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APPLICATION FILED JUNE 12. I915. 1,218,9-1 6. Patented Mar. 13, 1917.

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JOSEPH WEATHERBY, OF NEW CUMBERLAND, PENNSYLVANIA, ASSIGNOR, BY DIRECTAND MESNE ASSIGNMENTS, T0 ELECTRIC ORE SEPARATOR COMPANY, OF NEW CUM-BERLAND, PENNSYLVANIA, A CORPORATION OF DELAWARE.

METHOD AND APPARATUS FOR SEPARATING MAGNETIC ORES.

Specification of Letters Patent.

Patented Mar. 13, 1917.

Application filed June 12, 1915. Serial No. 83,747.

a citizen of the United States, residing at.

New Cumberland, in the county of Cumberland and State of Pennsylvania,have invented certain new and useful Improvements in Methods andApparatus for Separating Magnetic Ores; and I do hereby declare thefollowing to be a full, clear, and exact description of the same,reference being had to the accompanying drawings, forming part of thisspecification, and to the figures and letters of reference markedthereon.

This invention relates to improvements in the treatment ofmagnetic oresin a subdivided mixture consisting of particles having differentdegrees'of magnetic, permeability.

In magnetic separators heretofore designed for the separation ofmagnetic ore particles from gangue materials, it has been found that themagnetic particles on entering the magnetic field will form into thickgroups or clusters incidentally entangling within the clusters suchgangue materials as might be between the magnetic particles be foreentering the magnetic field; thus the gangue material is carriedmechanically to the discharge, and a clean separation of the magneticfrom the non-magnetic particles cannot be obtained.

Many methods have been tried to overcome this fault, among these,feeding the ore one grain thick, which in very fine ore particles resultin small capacity per machine A comparatively weak magnetic field issometimes used, which results in great loss of values to the gangue,with little improvement in the magnetic concentrate. Another method usedwith more success is the placing of many magnetic poles adjacent to oneanother, but of opposite sign, the ore being conveyed over or under themagnet poles by a suitable carrier. The magnetic particles leap to thefirst pole in clusters as before described, thence are thrown or carriedto the following poles in regular order. Since the magnetic particleshave magnetic polarity, they are compelled to turnover and expose theirpole of opposite sign to that of the magnet pole in whose influence theyare progressed. This-"method shakes out considerable of the gangue thatis close to the surface of the clusters and causes the particles toarrange themselves in layers or stratas in accordance with theirmagnetic permeability, but since-the clusters turn over in masses orsheets, the gangue that is held deeper in the mass is progressedmechanically to the concentrate discharge.

One object of the present invention is to preliminarily effect apractically complete stratification of the ore particles with themagnetic portion superposed or in the form of a sheet which may bereadily separated or 1 lifted away from the underlying gangue.

Another object is to prevent the formation of fingers or clusters ofmagnetic material during Stratification, whereby entanglement of gangueparticles is prevented.

Another object is to provide a cheap and eflective form of magneticseparator which will effectively stratify and separate the ore in athick layer or stream and at high speed, whereby the capacity of theapparatus is greatly augmented.

When magnetic ore is broughtwithin the influence of a rapidlyalternating magnetic field, and especially when carried through an airgap between oppositely located pole pieces, the magnetic particles tendto revolve at great speed, due to the reversals of the current, and thefact that each particle has magnetic polarity. Each magnetic particletries to adjust itself parallel with the. lines of magnetic force withits poles in proper relation to the magnet. Each individual magneticparticle tries to lock itself in contact with its neighbor, but isprevented from doing so by the surrounding gangue material and itsviolent revolution. This agitation which takes on the characteristics ofa violent ebullition of the magnetic particles brings the magneticparticles to the surface of the gangue for freedom of action and repelssuch gangue as interferes with their movement.

I have discovered that should the current be suddenly reversed in one ofthe magnets so that the magnets become opposed to one another inimproper magnetic relation so that the magnetic circuit in the air gapbetween the magnets become neutral, the magnetic ore particles will beviolently repelled one from the other and from magnet poles, thuspreventing the formation of fingers or clusters in the magnetic fieldand by periodically subjecting the traveling sheet or stream of ore tothe influence of the rapidly alternating field and to the opposedmagnetic fields the ore will be stratified with the magnetic content inthe form of a top layer which as it recedes from the field of magneticaction will be practically quiescent and in condition to be readilyseparated or lifted off of the underlying gangue content.

The invention may be carried into effect in various forms of apparatusand a simple easily understood form is shown in the accompanyingdrawings, in which:

Figure 1 is a side elevation of a magnetic ore separator for carryingout the improved method, well known parts being omitted or indicated ingeneral outline only.

Fig. 2 is a transverse section taken in a plane indicated by the line 22of Fig. 1, looking in the opposite direction to that indicated by thearrow.

Fig. 3 is an enlarged transverse section of a conveyer belt showing themixture after it has been stratified into layers.

Fig. 4 is a diagram showing one form of apparatus for obtainingalternate attractive and repulsive magnetic fields.

Fig. 5 is a diagrammatic representation of the changes in polarity ofthe magnetic fields when the apparatus shown in Fig. 4 is in operation.

Fig. 6 is a diagram showing a modified form of apparatus for obtainingalternate attractive and repulsive magnetic fields.

Fig. 7 is a diagrammatic representation of the changes in polarity ofthe fields when the apparatus shown in Fig. 6 is in operation.

Like reference characters in the several figures indicate the sameparts.

As shown in Fig. 1, the principal parts of a magnetic separatorembodying the present improvements are supported in a suitable frameworkA having at one end thereof a hopper B of any well known constructionand suspended from upper longitudinal frame members a and a. Located inposition to receive material discharged from the hopper B is a conveyer,consisting preferably of an endless belt C made of the usual rubbercovered fabric and mounted on pulleys c and c. The pulleys are suitablyjournaled on the frame members (1 a and the belt is arranged to bedriven in the direction indicated by the arrow in Fig. 1.

Securely mounted between frame members a', a and located below theconveyer belt C is an electro-magnet D having coils d, d and pole pieces01 01 Adjustably suspended above the belt is a second electromagnet Ehaving coils e, e and pole pieces e e Magnet E is arranged directly overmagnet D in such manner that when either magnet E or D is energized, amagnetic circuit will be completed through the air gap located betweenthe magnets. Magnet E is preferably so suspended from the framework thatadjustment is provided of the air gap between the magnets. For thispurpose magnet E is provided with lugs ein which are screwed bolts e Thebolts 6 'are screwed into the upper longitudinal frame members a, a, andare provided with lock nuts 0 which permit each end of magnet E to beraised or lowered as desired. Suspended above the discharge end ofconveyer belt C, i. 6., the end beyond magnets E, D, is a separator beltF mounted at its ends '"on pulleys f, f suitably journaled on framemembers a, a. The belt F is driven to move in the same general directionas belt C. Adjustably suspended from frame members a, a in the samemanner as magnet E is a lifting magnet G having coils g, g and poles g 9The magnet G is suspended from lugs g in which are screwed bolts 9adjustably mounted in the frame by nuts 9. It will be noted that magnetG is so arranged that the lower run of separator belt F is interposedbetween it and conveyer belt C and pole g? is located above thedischarge end of conveyer belt C.

Suitably mounted within the frame members a a and located approximatethe discharge end of conveyer belt C and under magnet G are dischargebins or chutes H consisting of a chute h for gangue materials, a chute hfor middlings or magnetic particles of ore that are mechanicallyconnected or embedded in gangue material, and compartment k for themagnetic particles of greatest magnetic permeability or the magneticconcentrate. Below the discharge ends of the chute are conveyeror-carrier belts h 72., k respectively, these being arranged to carryaway the separated layers to their proper destination.

Referring now particularly to Figs. 4 and 5, a source of alternatingcurrent supply is indicated at J having main circuit wires 7' and j.Leadin from a main circuit wire 7'. to a coil d o electromagnet D is aconducting wire j and leading from main circuit wire j to a coil d ofelectro-magnet D is a conducting wire 7'. 'A conducting wire j connectscoil 0 of electro-magnet E with main circuit-wire j and a conductingwire 9' connects coil 6' of electro-magnet E with a brush Z of a rotarymake-and-break L. The other brush Z of rotary make-and-break L isprovided with oppositely disposed contact surfaces 1 ,1 electricallyconnected as shown for the purpose of intermittently connecting thecoils of electro-magnet E with the source of alternating current supplyJ Interposed' between brush 1 and conducting wire j is a condenser M ofsufiicient capacity to absorb the counter-electromotive force orback-kick from the coils of electro-magnet E when the circuit is brokenby rotary makeand-break L, and to prevent a heavy arcing discharge atthe brus es Z, 2'.

In Fig. 5 the changes in polarity of pole pieces a and (Z arerepresented, the signs Ins and minus denotin magnetic polarity.

he sinuous line 0' in icates the alternating current passing throughpole piece 03 of electro-magnet D and the broken sinuous lines 0 denotethe alternating current as it intermittently passes through pole piecese of electro-magnet E.

It will be noted that magnet D is continuously connected with the sourceof alternating current supply through connecting wires 7', j, and magnetE is only connected with the source of alternating current supply whenthe contact surfaces Z Z are in engagement with brushes Z, Z. Magnet Eis so arranged with respect to magnet D that when an alternating currentis flowing through the coils of magnet E pole pieces 6 e of magnet E arein improper relation to the magnet poles d (Z3 of magnet D, thus causingthe lines of magnetic force from each magnet to oppose each other. WVhenthe current is disconnected from magnet E energized magnet D inducesmagnetic action in magnet E, causing lines of magnetic force to flowacross the air gap between the magnets through magnet E, completing itsmagnetic circuit, and energizing both magnets in proper relation withrespect to each other.

When, however, electro-magnet E is connected to the source ofalternating current supply J through rotary make-and-break L, a magneticfield is created about the poles e e of magnet E which magnetic field isopposed to the magnetic field of electromagnet D, thus causing the linesof magnetic force in the air gap between the two magnets to flow inopposite directions from the direction of flow when magnet E is notconnected with the source of alternating current supply J. This actionis best represented by the series of oblong blocks e denoting changes inpolarity of magnetic pole e and the series of oblong blocks drepresenting the changes in polarity of pole 4Z when the rotarymake-and-break L' is in operation and electro-magnet E is beingintermittently connected with the source of alternating current supplyJ. In the said diagram it will be noted that when magnet E isdisconnected from the source of current supply, pole e is in propermagnetic relation with respect to pole 0Z pole 9 being shown as ofpositive polarity and pole d of minus polarity, the changes in polarityof the two poles taking place in accord with the oscillations of thealternating current flowing through the coils of electro-magnet D andthe induced magnetic field created in the air gap between the twoelectro-magnets E and D. At the times when an alternating current 0 ispassing through the coils of electro-magnet the pole piece e is inimproperrelation with respect to pole piece (1 it being of positivepolarity at the same time that pole piece d is of positive polarity. Inthis manner when electro-magnet E is connected by the rotarymake-and-break L with the source of alternating current supply J themagnetic field of electro-magnet E is opposed to the magnetic field ofelectro-magnet D. C is a diagrammatic representation of the conveyerbelt carrying the mixture of particles of different degrees of magneticpermeability through the air gap of the magnets when the rotarymake-and-break L is in operation.

The operation is as follows:

Assuming that the rotating connecting device L has been started torevolve at a fairly high speed, and at the present instant the currentis temporarily disconnected from magnet E. The magnetic lines of forceare flowing to complete their proper circuit from magnet D to andthrough the air gaps and ore, and through magnet E. The ore particles onthe belt are now within a rapidly alternating magnetic field and themagnetic particles are compelled to revolve or whirl in proportion tothe alternations, to present their respective poles parallel with themagnetic lines of force. They also want to grou together in propermagnetic relation wit one another and in contact, but are prevented fromdoing so by the surrounding gangue particles. In their violent agitationthey throw the gangue aside and leap to the surface of the ore mass andthence many of them getting-into contact with one another leap in awhirling mass toward pole e Before, or after they arrive in contactwith. pole piece e the rotating connecting device connects magnet E incircuit; the magnetic circuit is distorted and opposed and the magneticparticles are violently thrown back on the top of the progressing ganguematerial, only to be again attracted and repelled many times before theyfinally travel through the field between the pole pieces of the magnets.Magnet E is tiltedas shown to gradually weaken the attraction so theaction will not be so violent as the ore progresses out of the field.

The ore on leaving the alternating zone is spread out on the belt inlayers or stratas as shown in Fig. 3 of the drawing, where 0 representsthe non-magnetic gangue layer next to the conveyer belt. 0 representsthe sluggish middlings or mechanically combined particles on top of thegangue layer, and 0 represents the high grade magnetic ore particles orconcentrate as a top layer. The ore progresses in this condition to thedischarge end of the conveyer belt where it comes under the influence ofpole g of a powerful direct current magnet G. The top -magnetic layer ofore, together with the lesser magnetic middlings underneath, leap in asheet or mass to get into contact with pole g, the front edge of whichis adjusted close to the inner side of the discharge belt F. The outerside of the rapidly moving belt F is interposed between the ore and thepoles of the magnet G, the magnet G being adjusted on an angle to weakenthe attraction of pole g and to taper off the magnetic strength. The oreparticles coming into contact with the rapidly moving belt under pole garethrown toward pole g and owing to the weakening magnetic strength ofthe field, the lesser magnetic middlings product drop into receptacle kand thence fall to conveyer belt 72;. The magnetic concentrate particlesare thrown into receptacle 72, and drop to conveyer belt 72. while thenon-magnetic gangue material falls ofi' the conveyer belt 0 intoreceptacle 7:. and drop to conveyer belt It.

In Figs. 6 and 7 of the drawing are shown diagrammatic representationsof a modified arrangement for obtaining alternate attractive andrepulsive magnetic fields. Magnet D is supplied with an alternatingcurrent through main circuit wires j, y", and the source of alternatingcurrent supply J. Magnet E, however, iscontinuously supplied with adirect current. generator is indicated at K having a main circuit wireis connected with the coil 6 of electro-magnet E, and a main circuitwire is connected with a rheostat N. The rheostat N in turn is connectedby a conducting wire k with the other coil '6 of the electro-mag- 'netE. The current in magnet E may be adjusted by rheostat N to obtain equalmagnetic strength in both magnets. When cur-- rent is turned on in bothmagnets, the polarity of a pole piece 6 of electro-magnet E (see Fig. 7)is constant because of the fact that electro-magnet E is being suppliedwith a direct or continuous current. Electromagnet D, however, issupplied with an alternating current, and the oscillation of thealternating current changes the polarity of pole piece d ofelectro-magnet D. In this way the respective magnets D, E, are in propermagnetic relation during one half the cycle of alternating current 0 asshown in Fig. 7 and in improper magnetic relation during the other halfof the cycle of the alternating current. According to this arrangementthe attractive and repulsive magnetic fields created alternate withgreat speed, and the magnetic particles will be attracted and repelledin accordance with the frequency of the alternating current passingthrough electromagnet D.

What is claimed is 1. The process of separating a mixture of magneticand non-magnetic ore particles, which consists in subjecting the massfirst to the influence of a magnetic field, the polarity A, directcurrent of which is rapidly alternated and secondly, to the influence ofmagnetic fields of similar polarity located above and below the masswhereby the magnetic particles are alternately set into violentagitation or ebullition and caused to repel each other and settle in asurface layer on the non-magnetic particles.

2. The process of separating a mixture of magnetic and nonmagnetic oreparticles, which consists in supporting the mass and subjecting it firstto the influence of a magnetic field between pole pieces of oppositesign the polarity of which is rapidly alternated and, secondly to theinfluence of a magnetic field between pole pieces of similar sign,whereby the magnetic particles are alternately agitated in the mass andcaused to rise to the surface and are caused to repel and lie inert as asurface layer on the nonmagnetic particles.

3. The process of separating a mixture of magnetic and non-magnetic oreparticles, which consists in supporting the mass and subjecting it tothe influence of a constantly and rapidly alternating magnetic fieldbetween oppositely located pole pieces which are periodically ofopposite sign and similar sign.

4. A. method of separating a mixture of magnetic and non-magneticparticles which consists in bringing the mixture under the influence ofa magnetic field of constantly and rapidly alternating polarity, thecharacteristics of which are such that a magnetic condition is inducedin the magnetic particles to impart a spinning motion thereto causingthem to free themselves from the non-magnetic particles andintermittently subjecting them to the influence of a repulsive magneticfield adapted to cause the particles to repel one another whereby themagnetic particles are alternately under the influence of alternatingand repulsive magnetic fields.

5. A method of separating a mixture of magnetic and non-magneticparticles which consists in bringing the mixture under the influence ofa magnetic field of constantly and rapidly alternating polarity, thecharacteristics of which are such that a magnetic condition is inducedin the ma etic particles causing them to revolve and ree themselves fromthe non-magnetic particles, and then, while the magnetic partlcles arestill in the area sensitive to the magnetic forces, subjecting them tothe influence of a repulsive magnetic field of constantly and rapidlyalternating polarity.

6. A method of separating a mixture of magnetic and non-magneticparticles which consists in bringing the mixture under the influence ofa magnetic field of constantly and rapidly alternating polarity, thecharacteristics of which are such that a magnetic condition is-inducedin the magnetic particles to impart a rotary motion thereto causing themto free-themselves from the non-magnetic particles, and, while themagnetic particles are still'in the area sensitive to the magneticforces intermittently subjecting them to the influence of a repulsivemagnetic field of constantly and rapidly alternating polarity wherebythe magnetic particles are alternately under the influence ofalternating and repulsive magnetic fields.

8. A method of separating a mixture of magnetic and non-magneticparticles which consists in bringing the mixture under the influence ofa magnetic field induced b the flow of an alternating current, Where y amagnetic condition is induced in the magnetic particles causing them torevolve and free themselves from the non-magnetic particles and, whilethe magnetic particles are still in the area sensitive to the magneticforces, intermittently subjecting them to the influence of a repulsivemagnetic field whereby the magnetic particles are alternately under theinfluence of an alternating and a repulsive magnetic field.

9. A method of separating a mixture of particles whose characteristicsare diflerent degrees of magnetic permeability, which consists inbringing the mixture under the influence of a magnetic field thepolarity of which is rapidly alternated whereby a magnetic condition isinduced in the magnetic particles causing them to revolve, then, whilethe particles are still in the area sensitive to the magnetic forcessubjecting them to the influence of a repulsive magnetic field, the

olarity of which is rapidly alternated, and, ally, bringing thestratified mixture under the influence of a magnetic field of graduallydecreasing intensity, whereby the stratified layers of particles areseparated in the order of their magnetic characteristics. 1 10. A methodof separating a mixture of particles whose characteristics aredifferent,

degreesof magnetic permeability which consists in bringing the mixtureunder the influence of an intermittent magnetic field whereby a magneticcondition is induced in the magnetic particles, causing them to revolveand free themselves from the non-mag netic particles, then, while theparticles are still in the area sensitive to the magnetic forces,intermittently subjecting them to the influence of an intermittentrepulsive magnetic field, and, finally, bringing the stratified mixtureunder the influence of a magnetic field of gradually decreasing intensitwhereby the stratified layers of separated in the characteristics.

11. In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means for creating a magneticfield the polarity of which is constantly and rapidly alternated tocause the magnetic particles of the mixture to revolve and freethemselves from the non-magnetic particles, means for advancing the.mixture into said magnetic field, and means, operative while the mixtureis still in the field, for subjecting the mixture to a repulsivemagnetic action.

12. In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means for creating analternating magnetic field to cause the magnetic particles of themixture to revolve and free themselves from the non-magnetic particles,means for advancing the mixture into the said alternating magnetic fieldand means, operative while the mixture is still in the area sensitive tothe magnetic forces for intermittently subjecting the mixture to arepulsive magnetic action causing said particles to repel one another,whereby the mixture is alternately under the influence of alternatingand repulsive magnetic fields.

13. In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means for creating a magneticfield of constantly and rapidly alternating polarity to cause themagnetic particles of the mixture to revolve and free themselves fromthe non-magnetic particles, means for advancing the mixture into thefield and means, operative while the mixture is still in the areasensitive to the magnetic forces to change the field into a repulsivemagnetic field of constantly and rapidly alternating polarity to causethe magnetic particles to repel one another.

particles are order of their magnetic 14. In an apparatus for separatinga mix-- ticles to ,repelone another whereby the mix-' ture is under theinfluence of a magnetic field whose characteristics are intermittentlychanged to cause the magnetic particles to first revolve and then repelone another.

15. In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means forcreating alternatelyattractive repulsive magnetic fields adapted to stratify the material,means for passing the mixture through said fields and means formagnetically separating the material so Stratified.

16. In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means for creatingalternately attractive and repulsive magnetic fields of constantlychanging polarity adapted to stratify the material, means for passingthe mixture through said fields and means for magnetically separatingthe material so stratified.

17. In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means for creatingalternately alternating and repulsive magnetic fields of graduallydecreasing intensity, and means for passing the mixture through saidfields.

18.'In an apparatus for separating a mixture of magnetic andnon-magnetic particles, the combination of means for creatingalternately alternating and repulsive magnetic fields each of constantlychanging polarity and of gradually decreasing intensity, and

means for v passing the mixture through said fields.

19. In an apparatus for separating a mixture of particles whosecharacteristics are different degrees of magnetic permeability, thecombination of means for creating alternately attractive and repulsivema etic fields, means for advancing the mixture through said fieldswhereby the stratification of the mixture into layers of particles inaccord with their magnetic permeability .characteristics is effected,means for creating another magnetic field of gradually decreasingintensity, and means for advancing the Stratified mixture into the lastnamed magnetic field whereby the stratified layers of particles areseparated in the order of their magnetic characteristics.

20. An apparatus for separating ore mixtures consisting of particleswhose characteristics are different degrees of magnetic per- JOSEPHWEATHERBY.

